幾條有趣的小學四年級算術問題

前言
上個月中,信堅到曼哈頓 (Manhattan) 含飴弄孫,順便過感恩節。孫子紘燁先生,剛上小學四年級。帶回了幾題學校的算術作業,也順便考考阿公。(只能用算數,不准用代數。因為小學生還沒學代數。)

這可把阿公考倒了。因為我們在小學裡沒有學到如何解這種算數問題。才知算術是活的,不是死的數字。大家可以考考自己或自己的小孩,測試一下大家的算術能力。

一、三條小學四年級的算術問題
1. Amy began with 5 marbles for every 3 marbles that Tara had. After Amy gave 1 marble to Tara, then 3 time Tera had is equal to twice Amy had. How many marbles did Amy begin with?
如果Tara每擁有三顆彈珠,Amy 就擁有五顆彈珠。當Amy 給 Tara 一顆彈珠之後,Amy 所擁有彈珠的兩倍,就等於Tara 所擁有的三倍。請問,Amy 剛開始擁有幾顆彈珠?

2. Mr. Jackson was born on January 1, 1978. His daughter Leah was born on January 1, 2000. In what year was Mr. Jackson exactly three times as old as Leah?
傑克森先生出生於 1978年一月一日。 她的女兒莉亞出生於 2000年一月一日。問: 在何時傑克森的歲數是 Leah 的三倍?

3. If the Mother’s age is daughter’s age in reverse, and 13 years later, the mother’s age is twice of that of the daughter. What is the daughter’s age now?
如果媽媽的年紀是女兒歲數的位數顛倒,13年後,媽媽的年紀是女兒的兩倍,問: 現在女兒是幾歲? Continue reading